text: The development of large artillery pieces began by Burgundy. Originally a minor power, the duchy grew to become one of the most powerful states in 14th-century Europe, and a great innovator in siege warfare. The Duke of Burgundy, Philip the Bold (1363–1404), based his power on the effective use of big guns and promoted research and development in all aspects of gunpowder weaponry technology. Philip established manufacturers and employed more cannon casters than any European power before him.
  Whereas most European guns before 1370 weighed about 20 to 40 lbs (9–14 kg), the French siege of Château de Saint-Sauveur-le-Vicomte in 1375 during the Hundred Years War saw the use of guns weighing over a ton (900 kg), firing stone balls weighing over 100 lbs (45 kg). Philip used large guns to help the French capture the fortress of Odruik in 1377. These guns fired projectiles far larger than any that had been used before, with seven guns that could shoot projectiles as heavy as 90 kilograms. The cannons smashed the city walls, inaugurating a new era of artillery warfare and Burgundy's territories rapidly expanded.
  Europe entered an arms race to build ever larger artillery pieces. By the early 15th century both French and English armies were equipped with larger pieces known as bombards, weighing up to 5 tons (4,535 kg) and firing balls weighing up to 300 lbs (136 kg). The artillery trains used by Henry V of England in the 1415 Siege of Harfleur and 1419 Siege of Rouen proved effective in breaching French fortifications, while artillery contributed to the victories of French forces under Joan of Arc in the Loire Campaign (1429).
  These weapons were transformational for European warfare. A hundred years earlier the Frenchman Pierre Dubois wrote that a "castle can hardly be taken within a year, and even if it does fall, it means more expenses for the king's purse and for his subjects than the conquest is worth," but by the 15th century European walls fell with the utmost regularity.
  The Ottoman Empire was also developing their own artillery pieces. Mehmed the Conqueror (1432–1481) was determined to procure large cannons for the purpose of conquering Constantinople. Hungarian Urban produced for him a six-meter (20-foot) long cannon, which required hundreds of pounds of gunpowder to fire; during the actual siege of Constantinople the gun proved to be somewhat underwhelming. However, dozens of other large cannons bombarded Constantinoples walls in their weakest sections for 55 days, and despite a fierce defense, the citys fortifications were overwhelmed.